OEM mufflers?!

[Supercharged111]

The reason the mufflers dont last, and the welds look like poop, is because the mufflers are built in China, or another country like that. The metal is inferior as is the welding. As for a power difference, yes. Doing a less restrictive exhaust system will not only help with power, but will also give better MPHs. One of the things that help with cab exhaust noise is to run the exhaust out of the back of the truck, but if you go with an OE replacement muffler, this wont matter. OE mufflers are made from steel but are coated to prevent rust. They are a good quality steel that has a good coating over. They are NOT stainless steel. There are a lot of different grades of stainless steel. The better the grade, the more expensive it is. When I did my exhaust work, I got rid of the OE muffler first, and replaced that with 2 old school glass packs, 24 inches long, and ran true dual exhaust out of the back. I gained power and a little MPG. I then did shorty headers. I lost MPGs because I have a lead foot and like the power. Then I gutted the cats, and built 2 cat simulators. I gained the MPGs back that I lost with the headers, and even more power. Everyone likes the way my truck sounds. Its not real loud in the cab, and doesnt really have a drone at HWY speeds. It is only loud from behind the truck, and then really only when I nail the gas peddle. But what I like may not be what you like.

Ditching those itty bitty head pipes will unlock more power yet.

 

[kennythewelder]

Ditching those itty bitty head pipes will unlock more power yet.

When I am ready for an engine rebuild I will. A trans rebuild will come first, but Im running it all, till the trams quits. Then I will do the trans. After that I will have to decide what way I want to go with the engine. I do know this, the truck is and will be a daily driver, so it need to be reliable, give have way decent millage, and be able to out perform a new GM 5.3, oh waite, I already can Ha Ha. I have no plans to get radical with the truck. Small cam heads flat tops, and a performance trans rebuild.

 

[stutaeng]

I just looked at the '06 truck with aftermarket muffler. Says Flowmaster. In my industry bad quality welds are called pigeon poop welds, LOL.

The '04 truck muffler is OEM. Didn't measure them, but looks HUGE! It does look in better shape as well.

The PO only had the 06 truck from '13 until this year, so that muffler is not older than that...

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[Schurkey]

I've heard--but not verified--that Flowmaster is now made in China.

Gonna have to research claims that OEM mufflers aren't Stainless. Fairly sure they are, but I could be wrong.

 

[Supercharged111]

I've heard--but not verified--that Flowmaster is now made in China.

Gonna have to research claims that OEM mufflers aren't Stainless. Fairly sure they are, but I could be wrong.

I was at a shop last year and the guy was saying the same thing. That Flow master is likely a 50 series. As I recall they make one that fits the 6.0 well.

 

[stutaeng]

They are loud as hell! And drone-ey inside the cab. Now that I remember, when we were looking at the truck the PO told my brother he still had the original muffler...gonna see if I can get ahold of him. Or I'm just going to take it to a muffler shop.

Last time I was driving with the family, my wife freaked out when I hit the accelerator to pass a car.

My 00 K3500/5.7 also has Flowmaster muffler, but much more tolerable. It has a nice rumble...and I thought those were loud, LOL.

I'm a damn magnet for buying trucks with Flowmasters!

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[Supercharged111]

They are loud as hell! And drone-ey inside the cab. Now that I remember, when we were looking at the truck the PO told my brother he still had the original muffler...gonna see if I can get ahold of him. Or I'm just going to take it to a muffler shop.

Last time I was driving with the family, my wife freaked out when I hit the accelerator to pass a car.

My 00 K3500/5.7 also has Flowmaster muffler, but much more tolerable. It has a nice rumble...and I thought those were loud, LOL.

I'm a damn magnet for buying trucks with Flowmasters!

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Those aren't 50 series. That dual in/dual out looked like one.

 

[Schurkey]

I've got three of 'em--two on the 'Camino, one on my boat. Another waiting to go on my Nova--but it's been waiting for about a decade, I'll be lucky if it hasn't got rust holes from being on the shelf so long. My Flowmasters are so old that they were still advertised as "Made in USA". When they're gone, I will not be buying more Flowmasters. I see Flowmasters as a mistake I lived to tell about.

Had a Flowmaster Cat-Back on the '88 K1500; it was louder than I wanted and yet didn't really seem to offer more performance. The system rotted away after ten or eleven years. At the end, I had holes in the pipes and muffler big enough to push a kitten through. It's all gone, replaced with stainless pipe and a Magnaflow stainless muffler--still too damn loud.

The rotted-out muffler that was on the K2500 was a Flowmaster copy--Flowmaster construction, but without the Flowmaster name stamped into it. It came off in pieces. No idea how old it was.

 

[L31MaxExpress]

Walker Dynomax Bus Muffler. Have one on my Express van with headers and high flow cats. It was dual in/single out. Near stock in sound but flows very well. Its one massive, heavy SOB though.

Climbing a ~6% grade at highway speeds.

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[Supercharged111]

Walker Dynomax Bus Muffler. Have one on my Express van with headers and high flow cats. It was dual in/single out. Near stock in sound but flows very well. Its one massive, heavy SOB though.

Climbing a ~6% grade at highway speeds.

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Looks like I forgot to plug my Walker bus muffler here too. I have one on the dually. Nice, stockish quiet no idea on flow, but with a 4" tailpipe it can't be that bad.